1. Field of the Invention
The present invention relates to a printed circuit board and a method of making the same.
2. Description of the Related Art
An example of conventional printed circuit board is shown in FIG. 9 of the accompanying drawings. The illustrated circuit board includes an insulating substrate 200 having a rectangular configuration. Reference sign 200a refers to one of the two longitudinal edges of the substrate 200.
A plurality of conductive lands 210 (four shown in the figure) are formed on the upper surface of the substrate 200 arranged adjacent to the longitudinal edge 200a. The conventional circuit board also includes the same number of connection terminals 100 soldered to a respective one of the lands 210. As seen from FIG. 9, each terminal 100, made of a generally rectangular metal strip, includes a downward bent portion 100a and a horizontal portion 100b which is longer than the bent portion 100a. The terminal 100 is mounted on the substrate 200 with its bent portion 100a held in contact with the longitudinal edge 200a. Though not shown in FIG. 9, a protection circuit is formed on the lower surface of the substrate 200. A plurality of connectors 220 are provided on the lower side of the substrate 200.
To produce a functionally correct printed circuit board, each of the terminals 100 should be positioned accurately to the appropriate land 210. In the conventional device, however, this is rather difficult since the terminal 100 tends to be displaced accidentally when soldered to the land 210.
To address this problem, the terminals 100 may be fixed beforehand in a plastic frame 300, as shown in FIG. 10, with their relative positions properly adjusted. Such a terminal-frame assembly may be manufactured by insert molding. The assembly is then mounted on the substrate 200 so that the respective terminals 100 will be positioned correctly relative to the substrate 200.
With the use of the frame 300, the positioning of the terminals 100 can be performed more easily than when the individual terminals 100 are directly mounted on the substrate 200. Disadvantageously, however, the terminal-frame assembly adds to the thickness and weight of the resulting device. Also, the cost of the insert molding for making the terminal-frame assembly can be rather high.
The present invention has been proposed under the above circumstances, and therefore it is an object of the present invention to provide a compact, light and inexpensive printed circuit board for which the positioning of terminals is readily performed with high accuracy.
Another object of the present invention is to provide a method of making such an advantageous printed circuit board.
According to a first aspect of the present invention, there is provided a printed circuit board which includes: an insulating substrate provided with an obverse surface, a reverse surface and an edge extending between the obverse and the reverse surfaces; a conductive land formed on the obverse surface; and a terminal including a bent portion and mounted on the substrate to be connected to the land. The above-mentioned edge of the substrate is formed with a groove for receiving the bent portion of the terminal, so that the terminal as a whole will be correctly positioned relative to the substrate.
Preferably, the groove may have a flaring-out cross section. Specifically, the groove may be defined by a bottom surface and two slanted surfaces, wherein the bottom surface has a width substantially equal to the width of the bent portion of the terminal.
According to a preferred embodiment of the present invention, the bent portion received in the groove may extend toward the reverse surface of the substrate, but terminate short of the reverse surface.
According to a second aspect of the present invention, there is provided a printed circuit board which includes: an insulating substrate provided with an obverse surface, reverse surface, a first edge and a second edge opposite to the first edge, the first and the second edges extending between the obverse and the reverse surfaces; a conductive land formed on the obverse surface and arranged adjacent to the first edge; and a terminal mounted on the substrate to overlap the land. The terminal includes a bent portion held in contact with the first edge of the substrate. The land protrudes toward the second edge of the substrate from the terminal.
For the purposes of positioning the terminal more accurately, the first edge of the substrate may be formed with a groove into which the bent portion of the terminal is fitted.
According to a third aspect of the present invention, there is provided a battery pack which includes: a package; a battery held in the package; and a printed circuit board embedded in the package to be electrically connected to the battery. The printed circuit board may includes: an insulating substrate provided with a first edge and an opposite second edge, the first edge being formed with a flaring-out groove; a conductive land formed on the substrate and arranged adjacent to the first edge; and a terminal mounted on the substrate to overlap the land. The terminal includes a bent portion fitted into the flaring-out groove. The package is formed with an opening for exposing the terminal. The land protrudes toward the second edge from the terminal.
According to a fourth aspect of the present invention, there is provided a method of making a printed circuit board. The method includes the steps of: preparing a conductive strip provided with a bent portion; preparing an insulating substrate including an edge at which a groove is formed, a conductive land being arranged on the substrate adjacent to the groove; mounting the strip onto the substrate so that the strip overlaps the land; and soldering the strip to the land with the bent portion held in the groove of the substrate.
According to a fifth aspect of the present invention, there is provided a method of making a printed circuit board. The method includes the steps of: preparing a conductive strip provided with a bent portion; preparing an insulating substrate including a first edge and an opposite second edge, a conductive land being arranged on the substrate adjacent to the first edge; placing the strip on the land with the bent portion held adjacent to the first edge; and soldering the strip to the land with the land protruding toward the second edge of the substrate.
Preferably, the substrate may be formed with a groove arranged adjacent to the land, wherein the the strip is soldered to the land while the bent portion of the strip is fitted in the groove.
Other features and advantages of the present invention will become apparent from the detailed description given below with reference to the accompanying drawings.